Liquid nectar bird feeders are used for specifically attracting humming birds in the same manner as seed feeders are used to attract other birds. Some may consider liquid nectar feeders to be less convenient however, because of the liquid auto-feed structure. Filling liquid feeders commonly requires inversion of the feeder and certain liquid spillage from this action.
It is therefore desirable to have a liquid nectar feeder which minimizes liquid spillage during filling and which even avoids inversion during filling.